Plasticized composition and method of production

ABSTRACT

Plasticized compositions are produced by intimately mixing (a) a linear alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon and (b) an organic sulfone. Particularly preferred compositions comprise polymers of carbon monoxide and ethylene or polymers of carbon monoxide, ethylene and propylene, plasticized by the intimate presence therein of sulfolane.

This is a division of application Ser. No. 099,857 filed Sept. 22, 1987,now U.S. Pat. No. 4,795,773.

This invention relates to the class of linear alternating polymers ofcarbon monoxide and at least one ethylenically unsaturated hydrocarbonand particularly to novel plasticized compositions of the polymers.Additionally, the invention relates to a method for the production ofthe novel compositions.

The class of polymers of carbon monoxide and olefin(s), often referredto as polyketones, has been known for a number of years. Brubaker, U.S.Pat. No. 2,495,286 produced such polymers in the presence of freeradical initiators such as benzoyl peroxide. British Published PatentSpecification No. 1,081,304 produced such polymers in the presence ofalkylphosphine complexes of palladium salts as catalysts. Nozaki, U.S.Pat. No. 3,694,412, extended the process through the use ofarylphosphine complexes of palladium salts and certain inert solvents.

Particularly useful copolymers and terpolymers of carbon monoxide withat least one ethylenically unsaturated compound, e.g., ethylene orethylene and propylene, have been shown to be linear alternatingpolymers of the formula --CO(A)-- where A is the moiety obtained bypolymerization of the ethylenically unsaturated hydrocarbon through theethylenic unsaturation. For example, copolymers of carbon monoxide andethylene are of the formula --CO(CH₂ CH₂)--. The general process for theproduction of the linear alternating polymers is illustrated bypublished European Patent Application Nos.181,014 and 121,965. Theprocess generally involves the use of a catalyst formed from a GroupVIII metal compound wherein the metal is palladium, cobalt or nickel,the anion of a non-hydrohalogenic acid having a pKa below 2 and abidentate ligand of phosphorus, arsenic or antimony. The resultingpolymers are generally high molecular weight thermoplastic polymershaving utility in the production of structural articles such ascontainers for food and drink and parts for the automobile industry. Therelatively high melting point of the polyketone polymers is of value inmany applications, e.g., where a resulting shaped article is to besubjected to conditions of elevated temperature. For other applications,however, high temperature stability is not required and it would be ofvalue to provide plasticized compositions of polyketone polymers withreduced melting temperatures.

SUMMARY OF THE INVENTION

The present invention relates to plasticized compositions comprisinglinear alternating copolymers or terpolymers of carbon monoxide with oneor more ethylenically unsaturated hydrocarbons, which compositionsincorporate a quantity of a sulfone sufficient to plasticize thepolyketone polymer. In addition, the invention relates to a method ofproducing the plasticized compositions.

DESCRIPTION OF THE INVENTION

The polymers which are plasticized according to the process of theinvention are linear alternating polymers of carbon monoxide and atleast one ethylenically unsaturated hydrocrabon. Suitable ethylenicallyunsaturated hydrocarbons have from 2 to 20 carbon atoms inclusive,preferably from 20 to 10 carbon atoms inclusive, and are aliphatic suchas ethylene and other α-olefins including propylene, butene-1, octene-1and dodecene-1 or are arylaliphatic containing an aryl substituent in anotherwise aliphatic molecule, particularly an aryl substituent on acarbon atom of the ethylenic unsaturation. Illustrative of this latterclass of olefins are styrene, p-methylstyrene, p-ethylstyrene andm-methylstyrene. Preferred polyketone polymers are copolymers of carbonmonoxide and ethylene or terpolymers or carbon monoxide, ethylene and asecond a-olefin, particularly propylene.

Of particular interest are those polymers of molecular weight from about1,000 to about 200,000, particularly those of molecular weight fromabout 10,000 to about 50,000, and containing substantially equimolarquantities of carbon monixide and hydrocarbon.

Such polymers are produced by contacting carbon monoxide and theethylenically unsaturated hydrocarbon(s) under polymerization conditionsin the presence of a catalytic amount of a catalyst formed from acompound of the Group VIII metals palladium, cobalt or nickel, an anionof a nonhydrohalogenic acid of a pKa less than about 6, preferably lessthan about 2, and a bidentate ligand of phosphorus, arsenic or anitomy.Although the scope of the polymerization process is extensive, forpurposes of illustration the preferred Group VIII metal compound ispalladium acetate, the anion is the anion of an acid selected fromtrifluoracetic acid and p-toluenesulfonic acid and the bidentate ligandis 1,3-bis(diphenylphosphino)propane.

Polymerization is carried out at elevated temperature and pressure andin the gaseous phase or in the liquid phase in the presence of a liquiddiluent, e.g., methanol or ethanol. The reactants are contacted byconventional methods such as shaking or stirring and subsequent toreaction the polymer product is recovered as by filtration ordecantation. The polymer product may contain metal residues from thecatalyst which are removed if desired by contact with a solventselective for the residues. Production of this class of polymers isillustrated, for example, by Published European Patent Application Nos.181,014 and 121,965.

The physical properties of the polymer will be determined in part bymolecular weight and whether the polymer is a copolymer or a terpolymer.Typical melting points are from about 175° C. to about 300° C., morefrequently from abut 210° C. to about 260° C. The structure of thepolymers is that of a regular alternating copolymer of carbon monoxide,ethylene and any second ethylenically unsaturated hydrocarbon and thepolymer will contain substantially one carbon monoxide moiety for eachmoiety of unsaturated hydrocarbon. When terpolymers of carbon monoxide,ethylene and a second hydrocarbon i.e. a hydrocarbon of at least 3carbon atoms, are produced there will be at least about 2 unitsincorporating moieties of ethylene per unit incorporating a moiety ofthe second unsaturated hydrocarbon, preferably from about 10 to about100 units incorporating moieties of ethylene per unit incorporating aunit of the second unsaturated hydrocarbon. The polymer chain of thepreferred class of polymer products is thus illustratd by the formula

    --CO(CH.sub.2 --CH.sub.2)].sub.x [CO(B)].sub.y --

wherein B is the moiety obtained by polymerization through the ethylenicunsaturation of the second ethylenically unsaturated hydrocarbon. The--CO(CH₂ --CH₂)-- units and the --CO(B)-- units are found randomlythroughout the polymer chain and the ratio of y:x is no more than about0.5:1. In the modification of the invention which employs copolymers ofcarbon monixide and ethylene without units of a second ethylenicallyunsaturated hydrocarbon, the polymers are represented by the aboveformula wherein y=0. When y is other than 0, ratios of y:x from about0.01 to about 0.1 are preferred.

The plasticized compositions of the invention comprise the abovepolymers having intimately mixed therewith a plasticizing quantity of asulfone. Illustrative of sulfones useful as plasticizes in the presentinvention is the class of organic compounds of from 2 to 20 carbon atomsinclusive, particularly those of from 2 to 15 carbon atoms inclusive,characterized by the inclusion within the molecule of a --SO₂ -- sulfonelinkage. The substituents of the sulfone linkage are hydrocarbyl or aresubstituted hydrocarbyl wherein the substituents are non-reactive towardthe components of the plasticized composition. The substituents arealiphatic or aromatic and are monovalent or are such that thesubstituents taken together with the sulfone linkage form a heterocyclicring containing only carbon atoms besides the sulfur of the sulfonelinkage. A preferred class of such sulfones is represented by theformula

    R--SO.sub.2 --R

wherein R independently is alkyl including arylalkyl, aryl includingalkaryl, or such that both R groups taken together with the --SO₂ --linkage form a heterocyclic ring of from 4 to 8 carbon atoms in thering. Illustrative of alkyl groups are hydrocarbyl groups such asmethyl, ethyl, i-butyl, benzyl and octyl and substituted hydrocarbylalkyl groups such as 3-methoxypropyl, 3-(N,N-dimethylamino)octyl and4-hydroxybutyl. Suitable aryl substituents are hydrocarbyl groups suchas phenyl, 2-ethylphenyl, 2,4-dimethylphenyl and naphthyl andsubstituted hydrocarbyl aryl groups such as 4-methoxyphenyl,3-bromophenyl and 2-methyl-4-chlorophenyl. Heterocyclic sulfones usefulas plasticizer include hydrocarbyl sulfones such as tetramethylenesulfone (sulfolane), 2-methyltetramethylene sulfone,3,4-dimethyltetramethylene sulfone, trimethylene sulfone, hexamethylenesulfone and octamethylene sulfone. Substituted hydrocarbyl heterocyclicsulfones are illustrated by 2-chlorotetramethylene sulfone, and2,3-dihydroxytetramethylene sulfone. In general, the hydrocarbylsulfones are preferred over the substituted hydrocarbyl sulfones andbest results are typically obtained with a hydrocarbyl heterocyclicsulfone. Particularly preferred is tetramethylene sulfone, i.e.,sulfolane.

The plasticized polymer compositions are obtained by intimately mixingthe sulfone throughout the polyketone polymer. The amount of sulfone canbe varied, and the properties of the resulting composition will dependin part upon the proportion of sulfone it contains. Too little sulfonewill result in very little melting point lowering and the objectives ofincorporating a plasticizer may not be realized. On the other hand, toolarge an amount of plasticizer will result in a partial loss of thedesirable mechanical properties of the polyketone polymer. Amounts ofsulfone from about 5% by mol up to about 50% by mol, based on totalcomposition are useful with amounts from about 10% to about 25% by molon the same basis being preferred.

The plasticized compositions of the invention may also contain otherconventional polymer additives which are inert to the polymer andsulfone plasticizer such as blowing agents, mold release agents andantioxidants which may be added by blending, omitting or otherconventional methods.

The method of producing the plasticized composition is of considerableimportance since many of the more conventional methods of producingplasticized compositions are not effective for the sulfone-stabilizedcompositions of the invention. To obtain an effectively plasticizedcomposition, the polyketone polymer and the sulfone must be intimatelymixed. The preferred method of providing this degree of mixing isthrough a certain type of coprecipitation of the polymer and sulfone.The polymer is dissolved in a solvent for the polymer such ashexafluoroisopropanol, m-cresol or o-chlorophenol. The polymer solutionis then contacted with an excess of a solution of the sulfone in amaterial which is a solvent for the sulfone but a non-solvent for thepolymer. Such selective solvents include water, acetone and loweralcohols such as methanol and ethanol. The concentration of the polymersolution and of the sulfone solution is not critical and in both casesconcentrations of solute, i.e., polymer or sulfone, from about 0.1% byweight to about 15% by weight, based on total solution, are suitablewith the upper limit of concentration being limited by the solubility ofthe particular polymer or sulfone in the particular solvent. Largelybecause of solubility considerations, concentrations of polymer orsulfone from about 0.5% to about 10% by weight are preferred.

Production of the plasticized compositions is brought about by rapidcontact, as by mixing, of the polymer solution and the sulfone solution.The precipitated polymer-sulfone composition is recovered byconventional methods such as filtration or decantation and is used assuch or is mixed with other additives.

The plasticized polymer compositions are characterized by lower meltingpoints or initial soltening points than the polyketone polymers fromwhich they are prepared, as well as by increased tensile strength andimpact resistance. As such, the compositions are useful in thermoplasticapplications not requiring treatment at high temperature but in whichgreater ease of processing is desired.

The invention is further illustrated but not limited by the followingComparative Experiment (not of the invention) and the followingIllustrative Embodiments.

COMPARATIVE EXAMPLE I

A linear alternating copolymer of carbon monoxide and ethylene wasprepared by polymerization of an equimolar mixture carbon monoxide andethylene by conventional techniques in the presence of a catalyst formedfrom palladium acetate, the anion of trifluoroacetic acid and1,3-bis(diphenylphosphino) propane. The polymer was characterized by aninitial melting point of 257° C.

(a) Samples of this polymer, 1 g, were dissolved with heating in 50 mlof hexafluoroisoropyl alcohol (HFIPA) and then added to a large excessof water. The polymer which came out of solution was recovered byfiltration and dried in vacuo. The initial melting point of the polymerproducts were raised by as much as 20° C. when compared to that of theoriginal polymer.

(b) A 1 gram sample of the polymer was dissolved with heating in 250 mlof HFIPA and 0.5 g of sulfolane was added to the resulting solution.This mixture was then added to an excess of water and the polymerproduct which came out of solution was collected by filtration and driedin vacuo. A total of 0.95 g of polymer was recovered. The polymer had aninitial melting point of 267° C. and, according to NMR analysis,contained no sulfolane.

ILLUSTRATIVE EMBODIMENT I

(a) A 1 g sample of the polymer of Comparative Example I was dissolvedin 250 ml of HFIPA and then added to an excess of 5% sulfolane in water.A polymer product, 2.0 g, was recovered which, upon drying was found byNMR analysis to contain 35% by mol sulfolane. The initial melting pointwas 218° C.

(b) The procedure of part a) was repeated except that solution of 10%sulfolane in water was employed. The recovered polymer composition, 1.7g, was shown by NMR analysis to contain 26% by mol sulfolane. Theinitial melting point was 226° C.

(c) The procedure of part (a) was repeated except that a 1:3 (by volume)mixture of sulfolane and water was used. After separation and drying,the polymer composition, 2.6 g, was recovered and shown by NMR analysisto contain 48% by wt sulfolane. The initial melting point was 201° C.

ILLUSTRATIVE EMBODIMENT II

A 5 g sample of the polymer of Comparative Example I was dissolved, withheating, in 250 ml of HFIPA. On cooling, the solution was added to anexcess of a solution of 5% by weight of diphenylsulfone in acetone. Thepolymer composition thereby formed, 1.5 g after recovery and drying invacuo was shown by NMR to contain 10% by mol of diphenyl sulfone. Theinitial melting point was 233° C.

ILLUSTRATIVE EMBODIMENT III

Similar melting point lowerings are observed when m-cresol solutions ofcarbon monoxide/ethylene/propylene terpolymer are added to an excess ofsulfolane in water. The resulting polymer composition, which willcontain sulfolane, will have an initial melting point lower than that ofthe terpolymer.

What is claimed is:
 1. A process for the production of a plasticizedcomposition which comprises intimately mixing(a) a linear alternatingpolymer of carbon monoxide and at least one ethylenically unsaturatedhydrocarbon of from 2 to 20 carbon atoms inclusive, and (b) organicsulfone of from 2 to 20 carbon atoms inclusive wherein the substituentsof the --SO₂ -- linkage of said sulfone are of 2 to 20 carbon atomsinclusive and are hydrocarbyl or substituted hydrocarbyl in which thesubstituents are non-reactive toward the components of the plasticizedcomposition.
 2. The process of claim 1 wherein said mixing comprises theintimate mixing of a solution of said polymer in a solvent therefor anda solution of said sulfone in a solvent for said sulfone by anon-solvent for said polymer, and recovering the resulting plasticizedpolymer composition.
 3. The process of claim 2 wherein the polymer is ofthe formula

    --[CO(C.sub.2 H.sub.4)].sub.x [CO(B)].sub.y

wherein B is a moiety of an ethylenically unsaturated hydrocarbonpolymerized through the ethylenic unsaturation and the ratio of y:x isno more than about 0.5:1.
 4. The process of claim 3 wherein the sulfoneis represented by the formula R--SO₂ --R wherein R independently isalkyl, aryl or such that the R substituents together with the sulfonelinkage form a heterocyclic ring containing only carbon atoms besidesthe sulfur of the sulfone linkage.
 5. The process of claim 4 wherein Bis a moiety of propylene.
 6. The process of claim 4 wherein y=0.
 7. Theprocess of claim 6 wherein the solvent for the polymer ishexafluoroisopropyl alcohol or m-cresol and the solvent for the sulfonebut non-solvent for the polymer is acetone or water.
 8. The process ofclaim 7 wherein the sulfone is sulfolane.
 9. The process of claim 7wherein the sulfone is diphenyl sulfone.